CA2871529A1

CA2871529A1 - Pc/abs compositions with good thermal and chemical stability

Info

Publication number: CA2871529A1
Application number: CA2871529A
Authority: CA
Inventors: Thomas Eckel; Andreas Seidel; Martin Haussler; Burkhard Thuermer
Original assignee: Bayer MaterialScience AG
Current assignee: Covestro Deutschland AG
Priority date: 2012-04-27
Filing date: 2013-04-24
Publication date: 2013-10-31
Also published as: EP2841501B1; JP2017201035A; EP2841501A1; JP2015518513A; US8969448B2; CN104254570A; EP2657298A1; MX2014013033A; JP6199373B2; TW201406858A; CN104254570B; BR112014026341A2; TWI638851B; TW201811918A; KR20150013582A; US20130289177A1; WO2013160371A1; JP6698051B2

Abstract

The present invention relates to moulding compositions comprising polycarbonates and graft polymers and also, optionally, further additives and components with a low free bisphenol A content, these compositions possessing not only high chemical stability but also good thermal stability, more particularly a low tendency towards yellowing and a low propensity to degrade under thermal load. Furthermore, in one special, flame-retarded embodiment, the after-burn time in a UL94 classification is reduced.

Description

PC/ABS Compositions with good thermal and chemical stability The present invention relates to molding compositions made of polycarbonates and of graft polymers, and also optionally of other additives, and components which have not only high chemicals resistance but also good thermal stability, in particular little susceptibility to yellowing and little susceptibility to degradation on exposure to thermal stress.
In one particular, flame-retardant embodiment there is moreover a reduction in the after flame time in UL 94 classification.
Thermoplastic molding compositions made of polycarbonates and of ABS polymers have been known for a long time.
DE-A 1 170 141 describes molding compositions having good processability made of polycarbonates and of graft polymers of monomer mixtures made of acrylonitrile and of an aromatic vinyl hydrocarbon on polybutadiene.
DE-A 1 810 993 describes the improved heat resistance of polycarbonate in a blend with ABS graft polymers or with copolymers based on a-methylstyrene.
DE-A 22 59 565 and DE-A 23 29 548 relate to improved flow line strength of PC/ABS molding compositions, and both of these documents use graft polymers of a certain particle size as constituent of the ABS component.
DE-A 28 18 679 describes PC/ABS mixtures with particularly high low-temperature toughness when the ABS polymer comprises two graft copolymers with different degree of grafting.
EP-A 900 827 discloses impact-modified polycarbonate compositions with improved thermal stability comprising emulsion polymers which are in essence free from any types of basic component that degrade the polycarbonate. According to this application, polycarbonate compositions of this type, impact-modified with emulsion polymers exhibit shortcomings in thermal stability when these materials comprise basic impurities resulting from their production.
EP 0 363 608 describes polymer mixtures made of aromatic polycarbonate, of styrene-containing copolymer or graft copolymer, and also of oligomeric phosphates as flame retardant additives.
EP 0 704 488 describes molding compositions made of aromatic polycarbonate, of styrene-containing copolymers, and of graft polymers with a specific graft base, in certain quantitative proportions. These molding compositions can optionally be rendered flame-retardant with phosphorus compounds.

EP 747 424 describes thermoplastic resins which comprise phosphate compounds with molecular weight of from 500 to 2000 and phosphate compounds with molecular weight of from 2300 to 11 000 as flame retardants, and a large number of thermoplastic resins are listed here. The high molecular weights of the phosphorus compounds markedly impair the flow performance of the molding compositions.
EP 1 003 809 describes PC/ABS molding compositions which comprise oligomeric phosphorus compounds and graft polymers made of a graft base with a certain particle size. These molding compositions feature good mechanical properties, in particular also when they are subject to relatively high elasticity requirements.
EP 0 983 315 describes molding compositions made of aromatic polycarbonate, of graft polymer, and of a flame retardant combination made of a monomeric and oligomeric phosphorus compound. These molding compositions have high resistance to heat distortion and excellent mechanical properties (notched impact resistance and flow line strength).
None of the abovementioned documents describes the effect of the content of free, i.e. not chemically bonded, bisphenol A on thermal stability or the susceptibility of the polycarbonate molding compositions to yellowing, or the combination of these properties with improved chemical stability.
It was therefore an object of the present invention to provide polycarbonate molding compositions which have not only high chemicals resistance but also good thermal stability, in particular little susceptibility to yellowing and little susceptibility to degradation on exposure to thermal stress.
Another object of the present invention was to achieve the abovementioned properties in flame-retardant embodiments, and to reduce the after flame time in UL 94 classification.
Surprisingly, it has now been found that the abovementioned properties are obtained when the content, in the polycarbonate molding composition, of monomeric bisphenol A (BPA), i.e.
bisphenol A not chemically bonded within the polymer, does not exceed 70 ppm, based on the entire molding composition.
Free, i.e. not chemically bonded, BPA can by way of example be entrained as impurity in BPA-based polycarbonate, or as impurity in BPA-based flame retardants into the compositions, or else can be produced when the abovementioned components are exposed to thermal stress.

, BMS 111 220 PCT-NAT -3 - WO

The molding compositions thus constituted feature high chemicals resistance, good thermal stability, in particular little susceptibility to yellowing and little susceptibility to degradation on exposure to thermal stress, and also, in a flame-retardant embodiment, a reduced after flame time.
The invention provides thermoplastic molding compositions comprising A) from 51.0 to 99.5 parts by weight, preferably from 61.0 to 96.5 parts by weight, particularly preferably from 71.0 to 86.0 parts by weight, of at least one aromatic polycarbonate or polyester carbonate, B) from 0.5 to 49.0 parts by weight, preferably from 1.0 to 39.0 parts by weight, particularly preferably from 2.0 to 29.0 parts by weight, of at least one graft polymer, C) from 0.0 to 30.0 parts by weight, preferably from 1.0 to 20.0 parts by weight, particularly preferably from 3.0 to 15.0 parts by weight, of vinyl (co)polymer and/or polyalkylene terephthalate, D) from 0.0 to 20.0 parts by weight, preferably from 1.0 to 18.0 parts by weight, particularly preferably from 8.0 to 15.0 parts by weight, of at least one phosphorus-containing flame retardant, E) from 0.0 to 40.0 parts by weight, preferably from 0.5 to 10.0 parts by weight, particularly preferably from 1.0 to 6.0 parts by weight, of other conventional additives, where the sum of the parts by weight of components A) to E) gives a total of 100 parts by weight, and where the content of free bisphenol A in the entire composition is smaller than 70 ppm, preferably smaller than 50 ppm, more preferably smaller than 30 ppm, and preferably > 0.5 ppm, more preferably > 1.0 ppm, particularly preferably > 2 ppm.
hi one particular embodiment, the invention provides non-flame-retardant thermoplastic molding compositions comprising A) from 51.0 to 99.5 parts by weight, preferably from 61.0 to 93.0 parts by weight, particularly preferably from 71.0 to 91.0 parts by weight, of at least one aromatic polycarbonate, B) from 0.5 to 49.0 parts by weight, preferably from 2.5 to 39.0 parts by weight, particularly preferably from 5.0 to 35.0 parts by weight, of at least one graft polymer, , BMS 11 1 220 PCT-NAT - 4 -C) from 0.0 to 40.0 parts by weight, preferably from 1.5 to 30.0 parts by weight, particularly preferably from 3.5 to 20.0 parts by weight, of vinyl (co)polymer and/or polyalkylene terephthalate, E) from 0.0 to 40.0 parts by weight, preferably from 0.1 to 10.0 parts by weight, particularly preferably from 0.5 to 6.0 parts by weight, of other conventional additives, where the sum of the parts by weight of components A) to E) gives a total of 100 parts by weight, and where the content of free bisphenol A in the entire composition is smaller than 70 ppm, preferably smaller than 50 ppm, more preferably smaller than 30 ppm, and preferably > 0.5 ppm, more preferably > 1.0 ppm, particularly preferably > 2 ppm.
In one particular embodiment, the invention provides flame-retardant thermoplastic molding compositions comprising A) from 61.0 to 95.0 parts by weight, preferably from 66.0 to 90.0 parts by weight, particularly preferably from 71.0 to 85.0 parts by weight, of at least one aromatic polycarbonate, B) from 0.5 to 20.0 parts by weight, preferably from 2.0 to 15.0 parts by weight, particularly preferably from 5.0 to 12.0 parts by weight, of at least one graft polymer, C) from 0.0 to 20.0 parts by weight, preferably from 1.0 to 15.0 parts by weight, particularly preferably from 2.0 to 10.0 parts by weight, of vinyl (co)polymer and/or polyalkylene terephthalate, D) from 1.0 to 20.0 parts by weight, preferably from 2.0 to 18.0 parts by weight, more preferably from 4.0 to 16.0 parts by weight, particularly preferably from 7.0 to 15.0 parts by weight, of at least one preferably phosphorus-containing flame retardant, E) from 0.5 to 20.0 parts by weight, preferably from 1.0 to 15.0 parts by weight, particularly preferably from 1.0 to 10.0 parts by weight, of other conventional additives, where the sum of the parts by weight of components A) to E) gives a total of 100 parts by weight, and where the content of free bisphenol A in the entire composition is smaller than 70 ppm, preferably smaller than 50 ppm, more preferably smaller than 30 ppm, and preferably > 0.5 ppm, more preferably > 1.0 ppm, particularly preferably > 2 ppm.

The content of free bisphenol A is determined by dissolving the sample in dichloromethane and reprecipitating with methanol. The precipitated polymer fraction is removed by filtration, and the filtrate solution is concentrated by evaporation. The content of free BPA in the resultant filtrate solution is determined via HPLC with UV detection (external standard).
Particularly preferred molding compositions comprise, as component E), alongside optional other additives, from 0.1 to 1.5 parts by weight, preferably from 0.2 to 1.0 parts by weight, particularly preferably from 0.3 to 0.8 parts by weight, of a mold-release agent, e.g.
pentaerythritol tetrastearate.
Particularly preferred molding compositions comprise, as component E), alongside optional other additives, from 0.01 to 0.5 part by weight, preferably from 0.03 to 0.4 part by weight, particularly preferably from 0.06 to 0.3 part by weight, of at least one stabilizer, for example selected from the group of the sterically hindered phenols, phosphites, and mixtures thereof, and particularly preferably Irganox B900.
Particularly preferred flame-retardant molding compositions comprise, as component E), alongside optional other additives, from 0.05 to 5.0 parts by weight, preferably from 0.1 to 2.0 parts by weight, particularly preferably from 0.3 to 1.0 part by weight, of a fluorinated polyolefin.
Particular preference is moreover given to the combination of the three previously mentioned additives PTFE, pentaerythritol tetrastearate, and Irganox B900, as component E.

, BMS I I 1 220 PCT-NAT , - 6 -Component A
Aromatic polycarbonates and/or aromatic polyester carbonates according to component A which are suitable according to the invention are known from the literature or can be produced by processes known from the literature (for production of aromatic polycarbonates see by way of example Schnell, "Chemistry and Physics of Polycarbonates", Interscience Publishers, 1964, and also DE-AS (German Published Specification) 1 495 626, DE-A 2 232 877, DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for production of aromatic polyester carbonates e.g. DE-A 3 007 934).
Aromatic polycarbonates are produced by way of example via reaction of diphenols with carbonyl halides, preferably phosgene, and/or with aromatic diacyl dihalides, preferably dihalides of benzenedicarboxylic acids, by the interfacial process optionally with use of chain terminators, for example monophenols, and optionally with use of trifunctional or more than trifunctional branching agents, for example triphenols or tetraphenols. Another possible production method uses a melt polymerization process via reaction of diphenols with, for example, diphenyl carbonate.
Preference is given in the invention to polycarbonates produced by the interfacial process.
The OH end group concentration of the polycarbonates of the invention is with further preference smaller than 300 ppm, particularly preferably smaller than 250 ppm, very preferably smaller than 200 ppm.
The OH end group concentration is determined by means of infrared spectroscopy as described in Horbach, A.; Veiel, U.; Wunderlich, H., Makromolekulare Chemie [Macromolecular chemistry] 1965, vol. 88, pp. 215-231.
Diphenols for producing the aromatic polycarbonates and/or aromatic polyester carbonates are preferably those of the formula (I) (B). (B).
OH

HO
A ) ¨ P
where , BMS 1 1 1 220 PCT-NAT - 7 -A is a single bond, C1 to C5-alkylene, C2 to C5-alkylidene, C5 to C6-cycloalkylidene, -0-, -SO-, -CO-, -S-, -SO2-, or C6 to C12-arylene, onto which further aromatic rings optionally comprising heteroatoms can have been condensed, or a moiety of the formula (II) or (III) ) R \R6 (II) ? 11C H

(III) is in each case C1 to C12-alkyl, preferably methyl or halogen, preferably chlorine and/or bromine, x is mutually independently respectively 0, 1 or 2, is 1 or 0, and R5 and R6 can be selected individually for each X1, being mutually independently hydrogen or CI to C6- alkyl, preferably hydrogen, methyl or ethyl, XI is carbon and m is an integer from 4 to 7, preferably 4 or 5, with the proviso that on at least one atom X', R5 and R6 are simultaneously alkyl, preferably methyl or ethyl.
Preferred diphenols are hydroquinone, resorcinol, dihydroxydiphenols, bis(hydroxypheny1)-C1-05-alkanes, bis(hydroxyphenyl)-05-C6-cycloalkanes, bis(hydroxyphenyl) ethers, bis(hydroxyphenyl) sulfoxides, bis-(hydroxyphenyl) ketones, bis(hydroxyphenyl) sulfones and a,a-bis(hydroxyphenyl)diisopropylbenzenes, and also ring-brominated and/or ring-chlorinated derivatives of these.
Particularly preferred diphenols are 4,4'-dihydroxybiphenyl, bisphenol A, 2,4-bis(4-hydroxypheny1)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxypheny1)-3 .3.5 -trimethylcyclohexane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, and also di- and tetrabrominated or -chlorinated derivatives of these, for example 2,2-bis(3-chloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane or 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane. Particular preference is given to 2,2-bis(4-hydroxyphenyl)propane (bisphenol A).
The diphenols can be used individually or in the form of any desired mixtures.
The diphenols are known from the literature or can be obtained by processes known from the literature.
An example of a suitable chain terminator for producing the thermoplastic aromatic polycarbonates is phenol, p-chlorophenol, p-tert-butylphenol or 2,4,6-tribromophenol, or else long-chain alkylphenols, such as 412-(2,4,4-trimethylpentyl)]phenol, 4-(1,3-tetramethyl-butyl)phenol according to DE-A 2 842 005 or monoalkylphenols or dialkylphenols having a total of from 8 to 20 carbon atoms in the alkyl substituents, e.g. 3,5-di-tert-butylphenol, p-isooctylphenol, p-tert-octylphenol, p-dodecylphenol and 2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol. The amount of chain terminators to be used is generally from 0.5 mol% to 10 mol%, based on the total molar amount of the respective diphenols used.
The weight-average molar masses of the thermoplastic aromatic polycarbonates (Mw, measured via GPC (gel permeation chromatography with polycarbonate standard) are from 10 000 to 200 000 g/mol, preferably from 15 000 to 80 000 g/mol, particularly preferably from 23 000 to 32 000 g/mol and very particularly preferably from 26 000 to 32 000 g/mol.
The thermoplastic, aromatic polycarbonates can have any known type of branching, and specifically preferably via incorporation of from 0.05 to 2.0 mol%, based on the entirety of the diphenols used, of trifunctional or more than trifunctional compounds, such as those having three or more phenolic groups. It is preferable to use linear polycarbonates, and it is more preferable to use those based on bisphenol A.
Suitable materials are not only homopolycarbonates but also copolycarbonates.
Another possibility, to produce copolycarbonates of the invention according to component A, is to use from 1 to 25% by weight, preferably from 2.5 to 25% by weight, based on the total amount of diphenols to be used, of polydiorganosiloxanes having hydroxyaryloxy end groups. These are known (US 3 419 634) and can be produced by processes known from the literature. Polydiorganosiloxane-containing copolycarbonates are likewise suitable; the production of polydiorganosiloxane-containing copolycarbonates is described for example in DE-A 3 334 782.
Preferred polycarbonates, alongside the bisphenol A homopolycarbonates, are the copolycarbonates of bisphenol A with up to 15 mol%, based on the total molar amounts of diphenols, of diphenols other than those mentioned as preferred or as particularly preferred.
Preferred aromatic diacyl dihalides for producing aromatic polyester carbonates are the diacyl dichlorides of isophthalic acid, terephthalic acid, and diphenyl ether 4,4'-dicarboxylic acid and of naphthalene-2,6-dicarboxylic acid.
Particular preference is given to mixtures of the diacyl dichlorides of isophthalic acid and of terephthalic acid in a ratio of from 1:20 to 20:1.
Production of polyester carbonates also makes concomitant use of a carbonyl halide, preferably phosgene, as bifunctional acid derivative.
Chain terminators that can be used for producing the aromatic polyester carbonates are not only the abovementioned monophenols but also the chlorocarbonic esters of these, and also the acyl chlorides of aromatic monocarboxylic acids, which can optionally have substitution by C1 to C22-alkyl groups or by halogen atoms; aliphatic C2 to C22-monoacyl chlorides can also be used as chain terminators here.
The amount of chain terminators is in each case from 0.1 to 10 mol%, based on moles of diphenol in the case of the phenolic chain terminators and on moles of diacyl dichloride in the case of monoacyl chloride chain terminator.
Production of aromatic polyester carbonates can also use one or more aromatic hydroxycarboxylic acids.
The aromatic polyester carbonates can either be linear or can have any known type of branching (in which connection see DE-A 2 940 024 and DE-A 3 007 934), preference being given here to linear polyester carbonates.
Examples of branching agents that can be used are acyl chlorides of functionality three or higher, e.g.
trimesoyl trichloride, cyanuroyl trichloride, 3,3',4,4'-benzophenonetetracarbonyl tetrachloride, 1,4,5,8-naphthalenetetracarbonyl tetrachloride or pyromellitoyl tetrachloride, in amounts of from 0.01 to BMS 11 1 220 PCT-NAT . -10-1.0 mol% (based on diacyl dichlorides used) or tri- or polyfunctional phenols, such as phloroglucinol, 4,6-dimethy1-2,4,6-tri(4-hydroxyphenyphept-2-ene, 4,6-dimethy1-2,4,6-tri(4-hydroxyphenyl)heptane, 1,3 ,5-tri(4-hydroxyphenyl)benzene, 1,1,1-tri(4-hydroxyphenypethane, tri(4-hydroxyphenyl)phenylmethane, 2,2-b is [4,4-b i s(4-hydroxyphenyl)cyclohexyl] propane, 2,4-b is(4-hydroxyphenylisopropyl)phenol, tetra(4-hydroxyphenyl)methane, 2,6-bis(2-hydroxy-5' -methylbenzy1)-4-methylphenol, 2-(4-hydroxypheny1)-2-(2,4-dihydroxyphenyl)propane, tetra(444-hydroxyphenyli sopropyl] phenoxy)methane, 1,4-bis [4' ,4" -di hydroxytriphenyl)methyl] benzene, in amounts of from 0.01 to 1.0 mol%, based on diphenols used. Phenolic branching agents can be used as initial charge with the diphenols, and acyl chloride branching agents can be introduced together with the acyl dichlorides.
The proportion of carbonate structural units in the thermoplastic, aromatic polyester carbonates can vary as desired. The proportion of carbonate groups is preferably up to 100 mol%, in particular up to 80 mol%, particularly preferably up to 50 mol%, based on the entirety of ester groups and carbonate groups. The ester fraction of the aromatic polyester carbonates, and also the carbonate fraction thereof, can take the form of blocks or can have random distribution in the polyconden sate.
The thermoplastic aromatic polycarbonates and polyester carbonates can be used alone or in any desired mixture.
Component B
The graft polymers B comprise by way of example graft polymers with elastomeric properties which in essence are obtainable from at least two of the following monomers:
chloroprene, 1,3-butadiene, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate, and (meth)acrylic esters having from 1 to 18 C atoms in the alcohol component; i.e. polymers as described by way of example in "Methoden der Organischen Chemie" [Methods of organic chemistry] (Houben-Weyl), vol.
14/1, Georg Thieme-Verlag, Stuttgart 1961, pp. 393-406, and in C.B. Bucknall, "Toughened Plastics", Appl. Science Publishers, London 1977.
Examples of particularly preferred polymers B are ABS polymers (emulsion ABS, bulk ABS, and suspension ABS) as described by way of example in DE-OS (German Published Specification) 2 035 390 (=US patent 3 644 574) or DE-OS (German Published Specification) 2 248 242 (=GB patent 1 409 275), or in Ullmanns, Enzyklopadie der Technischen Chemie [Ullmann's encyclopedia of Industrial Chemistry], vol. 19 (1980), pp. 280 ff. The gel content of the graft base B.2 is at least 30%
by weight, preferably at least 40% by weight (measured in toluene).

The graft copolymers B are produced via free-radical polymerization, e.g. via emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization, preferably via emulsion polymerization or bulk polymerization.
Preferred polymers B have partial crosslinking and have gel contents of more than 20% by weight (measured in toluene), preferably more than 40% by weight, in particular more than 60% by weight.
Gel content is determined in a suitable solvent at 25 C (M. Hoffmann, H.
Kromer, R. Kuhn, Polymeranalytik I und II [Polymer analysis I and II], Georg Thieme-Verlag, Stuttgart 1977).
Preferred graft polymers B comprise graft polymers of:
B.1) from 5 to 95 parts by weight, preferably from 30 to 80 parts by weight, of a mixture B.1.1) from 50 to 95 parts by weight of styrene, a-methylstyrene, methyl-ring-substituted styrene, C1-C8-alkyl methacrylate, in particular methyl methacrylate, C1-C8-alkyl acrylate, in particular methyl acrylate, or a mixture of these compounds, and B.1.2) from 5 to 50 parts by weight of acrylonitrile, methacrylonitrile, C1-C8-alkyl methacrylates, in particular methyl methacrylate, C1-C8-alkyl acrylate, in particular methyl acrylate, maleic anhydride, C1-C4-alkyl- or -phenyl-N-substituted maleimides, or a mixture of said compounds, B.2) from 5 to 95 parts by weight, preferably from 20 to 70 parts by weight, of a rubber-containing graft base.
It is preferable that the glass transition temperature of the graft base is below -10 C.
Unless otherwise stated in the present invention, glass transition temperatures are determined by means of dynamic differential scanning calorimetry (DSC) in accordance with the standard DIN EN 61006 at a heating rate of 10 K/min, where the Tg is defined as mid-point temperature (tangent method) and nitrogen is used as inert gas.
Particular preference is given to a graft base based on a polybutadiene rubber.
Preferred graft polymers B are by way of example styrene- and/or acrylonitrile-, and/or alkyl-(meth)acrylate-grafted polybutadienes, butadiene/styrene copolymers, and acrylate rubbers; i.e.

BMS 11 1 220 PCT-I\JAT - 12 -copolymers of the type described in DE-OS (German Published Specification) 1 694 173 (= US patent 3 564 077) alkyl-acrylate- or alkyl-methacrylate-, vinyl-acetate-, acrylonitrile-, styrene-, and/or alkylstyrene-grafted polybutadienes, butadiene/styrene copolymers, or butadiene/acrylonitrile copolymers, polyisobutenes, or polyisoprenes as described by way of example in DE-OS (German Published Specification) 2 348 377 (= US patent 3 919 353).
Particularly preferred graft polymers B are graft polymers obtainable via graft reaction of I. from 10 to 70% by weight, preferably from 15 to 50% by weight, in particular from 20 to 40%
by weight, based on graft product, of at least one (meth)acrylate, or from 10 to 70% by weight, preferably from 15 to 50% by weight, in particular from 20 to 40% by weight, of a mixture of from 10 to 50% by weight, preferably from 20 to 35% by weight, based on mixture, of acrylonitrile or (meth)actylate and from 50 to 90%, preferably from 65 to 80%
by weight, based on mixture, of styrene, onto from 30 to 90% by weight, preferably from 40 to 85% by weight, in particular from 50 to 80%
by weight, based on graft product, of a butadiene polymer with at least 50% by weight, based on II, of butadiene moieties, as graft base.
The gel content of this graft base II is preferably at least 70% by weight (measured in toluene), the degree of grafting G preferably being from 0.15 to 0.55, and the median particle diameter d50 of the graft polymer B preferably being from 0.05 to 2 gm, preferably from 0.1 to 0.6 gm.
(Meth)acrylates I are esters of acrylic acid or methacrylic acid and of monohydric alcohols having from 1 to 18 C atoms. Particular preference is given to methyl methacrylate, ethyl methacrylate, and propyl methacrylate.
The graft base II can comprise, alongside butadiene moieties, up to 50% by weight, based on II, of moieties of other ethylenically unsaturated monomers, such as styrene, acrylonitrile, esters of acrylic or methacrylic acid having from 1 to 4 C atoms in the alcohol component (for example methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate), vinyl esters, and/or vinyl ethers. The preferred graft base II is composed of pure polybutadiene.
As is known, the graft monomers are not necessarily grafted entirely onto the graft base during the graft reaction, and therefore the expression graft polymers B in the invention includes those products that are obtained via polymerization of the graft monomers in the presence of the graft base.

The degree of grafting G denotes the ratio by weight of grafted graft monomers to the graft base, and is dimensionless.
The median particle size d50 is the diameter above and below which respectively 50% by weight of the particles lie. It can be determined by means of ultracentrifuge measurements (W. Scholtan, H. Lange, Kolloid, Z. und Z. Polymere 250 (1972), 782-796).
Other preferred graft polymers B are by way of example also graft polymers of (a) from 20 to 90% by weight, based on B, of acrylate rubber as graft base and (b) from 10 to 80% by weight, based on B, of at least one polymerizable, ethylenically unsaturated monomer where the glass transition temperature of this/these in the absence of a) resultant homo- or copolymers would be above 25 C, as graft monomers.
The glass transition temperature of the graft base made of acrylate rubber is preferably below -20 C, with preference below -30 C.
The acrylate rubbers (a) of the polymers B are preferably polymers of alkyl acrylates, optionally with up to 40% by weight, based on (a), of other polymerizable ethylenically unsaturated monomers.
Among the preferred polymerizable acrylates are C1-C8-alkyl esters, for example methyl, ethyl-, n-butyl, n-octyl, and 2-ethylhexyl esters, and also mixtures of said monomers.
Monomers having more than one polymerizable double bond can be copolymerized for crosslinking purposes. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids having from 3 to 8 C atoms and of unsaturated monohydric alcohols having from 3 to 12 C
atoms, or of saturated polyols having from 2 to 4 OH groups and from 2 to 20 C
atoms, e.g. ethylene glycol dimethacrylate, allyl methacrylate; polyunsaturated heterocyclic compounds, e.g. trivinyl and triallyl cyanurate; polyfunctional vinyl compounds, such as di- and trivinylbenzenes; and also triallyl phosphate and diallyl phthalate.
Preferred crosslinking monomers are allyl methacrylate, ethylene glycol dimethacrylate, diallyl phthalate, and heterocyclic compounds which have at least 3 ethylenically unsaturated groups.
Particularly preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl isocyanurate, trivinyl cyanurate, triacryloylhexahydro-s-triazine, triallylbenzenes.

The amount of the crosslinking monomers is preferably from 0.02 to 5, preferably from 0.05 to 2% by weight, based on graft base (a).
In the case of cyclic crosslinking monomers having at least 3 ethylenically unsaturated groups it is advantageous to restrict the amount to less than 1% by weight of the graft base (a).
Preferred "other" polymerizable, ethylenically unsaturated monomers which can optionally serve, alongside the acrylates, for the production of the graft base (a) are by way of example acrylonitrile, styrene, oc-methylstyrene, acrylamides, vinyl C -C6-alkyl ethers, methyl methacrylate, butadiene.
Preferred acrylate rubbers as graft base (a) are emulsion polymers which have at least 60% by weight gel content.
Other suitable graft bases are silicone rubbers with graft-active sites and with at least 40% gel content (measured in dimethylformamide), as described in the laid-open specifications DE 37 04 657, DE 37 04 655, DE 36 31 540, and DE 36 31 539, and also silicone-acrylate composite rubbers.
Component C
Component C comprises one or more thermoplastic vinyl (co)polymers C.1 and/or polyalkylene terephthalates C.2.
Suitable vinyl (co)polymers C.1 are polymers of at least one monomer from the group of the vinylaromatics, vinyl cyanides (unsaturated nitriles), (Ci-C8)-alkyl (meth)acrylates, unsaturated carboxylic acids, and also derivatives (such as anhydrides and imides) of unsaturated carboxylic acids.
Particularly suitable materials are (co)polymers of C.1.1 from 50 to 99 parts by weight, preferably from 60 to 80 parts by weight, of vinylaromatics and/or ring-substituted vinylaromatics such as styrene, a-methylstyrene, p-methylstyrene, p-chlorostyrene), and/or (CI-CO-alkyl (meth)acrylates, such as methyl methacrylate, ethyl methacrylate, and C.1.2 from 1 to 50 parts by weight, preferably from 20 to 40 parts by weight, of vinyl cyanides (unsaturated nitriles) such as acrylonitrile and methacrylonitrile, and/or (Ci-CO-alkyl (meth)acrylates, such as methyl methacrylate, n-butyl acrylate, tert-butyl acrylate, and/or unsaturated carboxylic acids, such as maleic acid and/or derivatives, such as anhydrides and imides, of unsaturated carboxylic acids, for example maleic anhydride and N-phenylmaleimide).

The vinyl (co)polymers C.1 are resin-like, thermoplastic, and rubber-free.
Particular preference is given to the copolymer of C.1.1 styrene and C.1.2 acrylonitrile.
The (co)polymers of C.1 are known and can be produced via free-radical polymerization, in particular via emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization. The average molecular weights Mw of the (co)polymers (weight averages, determined via light scattering or sedimentation) are preferably from 15 000 to 200 000.
The polyalkylene terephthalates of component C.2 are reaction products of aromatic dicarboxylic acids or of reactive derivatives thereof, for example dimethyl esters or anhydrides, and of aliphatic, cycloaliphatic, or araliphatic diols, or else are mixtures of said reaction products.
Preferred polyalkylene terephthalates comprise at least 80% by weight, preferably at least 90% by weight, based on the dicarboxylic acid component, of terephthalic acid moieties and at least 80% by weight, preferably at least 90 mol%, based on the diol component, of ethylene glycol moieties and/or 1,4-butanediol moieties.
The preferred polyalkylene terephthalates can comprise, alongside terephthalic acid moieties, up to 20 mol%, preferably up to 10 mol%, of moieties of other aromatic or cycloaliphatic dicarboxylic acids having from 8 to 14 carbon atoms or of aliphatic dicarboxylic acids having from 4 to 12 carbon atoms, e.g. moieties of phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4'-biphenyl-dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexanediacetic acid.
The preferred polyalkylene terephthalates can comprise, alongside ethylene glycol moieties and, respectively, 1,4-butanediol moieties, up to 20 mol%, preferably up to 10 mol%, of other aliphatic diols having from 3 to 12 carbon atoms or cycloaliphatic diols having from 6 to 21 carbon atoms, e.g.
moieties of 1,3-propanediol, 2-ethyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, cyclohexane-1,4-dimethanol, 3-ethy1-2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,2,4-trimethy1-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,5 -hexanediol, 1,4-di([3-hydroxyethoxy)benzene, 2,2-bis(4-hydroxycyclohexyl)propane, 2,4-dihydroxy-1,1,3 ,3-tetramethylcyc lobutane, 2,2-bis(4-3-hydroxyethoxyphenyl)propane and 2,2-bis(4-hydroxypro-poxyphenyl)propane (DE-A 2 407 674, 2 407 776, 2 715 932).
The polyalkylene terephthalates can be branched via incorporation of relatively small amounts of tri- or tetrahydric alcohols or tri- or tetrabasic carboxylic acids, e.g. according to DE-A 1 900 270 and US
Patent 3 692 744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane and trimethylolpropane and pentaerythritol.

BMS 11 1 220 PCT-NAT . -16-Particular preference is given to polyalkylene terephthalates which have been produced solely from terephthalic acid and from reactive derivatives thereof (e.g. from dialkyl esters thereof) and from ethylene glycol and/or from 1,4-butanediol, and to mixtures of said polyalkylene terephthalates.
Mixtures of polyalkylene terephthalates comprise from 1 to 50% by weight, preferably from 1 to 30%
by weight, of polyethylene terephthalate and from 50 to 99% by weight, preferably from 70 to 99% by weight, of polybutylene terephthalate.
The limiting viscosity number of the polyalkylene terephthalates preferably used is generally from 0.4 to 1.5 dl/g, preferably from 0.5 to 1.2 dl/g, measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25 C in an Ubbelohde viscometer.
The polyalkylene terephthalates can be produced by known methods (see by way of example Kunststoff-Handbuch [Plastics handbook], Volume VIII, pp. 695ff., Carl-Hanser-Verlag, Munich, 1973).
Component D
Phosphorus-containing flame retardants D for the purposes of the invention are preferably selected from the groups of the mono- and oligomeric phosphoric and phosphonic esters, phosphonate amines, and phosphazenes, and it is also possible here to use mixtures of a plurality of components selected from one or various of these groups, as flame retardants. Other halogen-free phosphorus compounds not specifically mentioned here can also be used alone or in any desired combination with other halogen-free phosphorus compounds.
Preferred mono- and oligomeric phosphoric or phosphonic esters are phosphorus compounds of the general formula (V) R¨(0) OX 0 P -- (0)7¨R4 (0)n (0)n R2 3_q (V) in which RI, R2, R3 and R4 are respectively mutually independently optionally halogenated C1 to C8-alkyl, respectively optionally alkyl-substituted, preferably C1 to C4-alkyl-substituted, and/or halogen-BMS 11 1 220 PCT-NAT . - 17 -substituted, preferably chlorine- or bromine-substituted, C5 to C6-cycloalkyl, C6 to C20-aryl or C7 to C12-aralkyl, is mutually independently 0 or 1, is from 0 to 30 and X is a mono- or polynuclear aromatic moiety having from 6 to 30 C atoms or a linear or branched aliphatic moiety having from 2 to 30 C atoms which can have OH-substitution and can comprise up to 8 ether bonds.
It is preferable that R1, R2, R3 and R4 are mutually independently C1 to C4-alkyl, phenyl, naphthyl or phenyl-Ci-C4-alkyl. The aromatic groups RI, R2, R3 and R4 can in turn have substitution by halogen groups and/or by alkyl groups, preferably chlorine, bromine and/or CI to C4-alkyl. Particularly preferred aryl moieties are cresyl, phenyl, xylenyl, propylphenyl or butylphenyl, and also the corresponding brominated and chlorinated derivatives thereof.
X in the formula (V) is preferably a mono- or polynuclear aromatic moiety having from 6 to 30 carbon atoms. This is preferably derived from diphenols of the formula (I).
n in the formula (V) can be mutually independently 0 or 1, and n is preferably equal to 1.
is integers from 0 to 30, preferably from 0 to 20, particularly preferably from 0 to 10, and in the case of mixtures in average values of from 0.8 to 5.0, preferably from 1.0 to 3.0, more preferably from 1.05 to 2.00 and very particularly preferably from 1.08 to 1.60.
X is particularly preferably C
= , 4110, C H2 = , 10 =
L) =

or chlorinated or brominated derivatives thereof, and in particular X is derived from resorcinol, from hydroquinone, from bisphenol A or from diphenylphenol. Particular preference is given to X derived from bisphenol A.
Phosphorus compounds of the formula (V) are in particular tributyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenyl cresyl phosphate, diphenyl octyl phosphate, diphenyl 2-ethylcresyl phosphate, tri(isopropylphenyl) phosphate, resorcinol-bridged oligophosphate and bisphenol-A-bridged oligophosphate. Particular preference is given to the use of oligomeric phosphoric esters of the formula (V) derived from bisphenol A.
Greatest preference is give to bisphenol-A-based oligophosphate according to formula (Va) as component D.
= ¨P

11'=0 I 3 e =

q = 1,1 (Va) The phosphorus compounds according to component D are known (cf. by way of example EP-A
0 363 608, EP-A 0 640 655) or can be produced analogously by known methods (e.g. Ullmanns Enzyklopadie der technischen Chemie [Ullmann's encyclopaedia of industrial chemistry], Volume 18, pp. 301ff. 1979; Houben-Weyl, Methoden der organischen Chemie [Methods of organic chemistry], Volume 12/1, P. 43; Beilstein Volume 6, P. 177).
It is also possible to use, as component D of the invention, mixtures of phosphates with different chemical structure and/or with identical chemical structure and with different molecular weight.
It is preferable to use mixtures with identical structure and different chain length, where the stated q value is the average q value. The average q value is determined by determining the composition of the phosphorus compound (molecular weight distribution) by means of high pressure liquid chromatography (HPLC) at 40 C in a mixture of acetonitrile and water (50:50), and using this to determine the average values for q.
It is also possible to use, as flame retardants, phosphonate amines and phosphazenes as described in W000/00541 and WO 01/18105.

The flame retardants can be used alone or in any desired mixtures with one another, or in a mixture with other flame retardants.
When the compositions of the invention are rendered flame-retardant, it is preferable that an antidripping agent is additionally present, preferably polytetrafluoroethylene (PTFE).
Component E
The composition can comprise other conventional polymer additives such as flame retardant synergists, antidripping agents (for example compounds of the substance classes of the fluorinated polyolefins, of the silicones, or else of aramid fibers), lubricants and mold-release agents (for example pentaerythritol tetrastearate), nucleating agents, stabilizers, antistatic agents (for example conductive carbon blacks, carbon fibers, carbon nanotubes, or else organic antistatic agents such as polyalkylene ethers, alkyl sulfonates, or polyamide-containing polymers) or else dyes and pigments.
Antidripping agent in particular used is polytetrafluoroethylene (PTFE) or PTFE-containing compositions such as masterbatches of PTFE with styrene- or methyl-methacrylate-containing polymers or copolymers, in the form of powder or in the form of coagulated mixture, e.g. with component B or C.
The fluorinated polyolefins used as antidripping agents are of high molecular weight, and have glass transition temperatures above -30 C, generally above 100 C, fluorine contents preferably from 65 to 76% by weight, in particular from 70 to 76% by weight, and median particle diameter d50 of from 0.05 to 1000 p,m, preferably from 0.08 to 20 nm. The density of the fluorinated polyolefins is generally from 1.2 to 2.3 g/cm3. Preferred fluorinated polyolefins are polytetrafluorethylene, polyvinylidene fluoride, tetrafluoroethylene/hexafluoropropylene copolymers, and ethylene/tetrafluoroethylene copolymers. The fluorinated polyolefins are known (cf. "Vinyl and Related Polymers" by Schildknecht, John Wiley & Sons, Inc., New York, 1962, pp. 484-494;
"Fluoropolymers" by Wall, Wiley-Interscience, John Wiley & Sons, Inc., New York, volume 13, 1970, pp.
623-654; "Modern Plastics Encyclopedia", 1970-1971, volume 47, No. 10 A, October 1970, McGraw-Hill, Inc., New York, pp. 134 and 774; "Modern Plastics Encyclopedia", 1975-1976, October 1975, volume 52, No.
10 A, McGraw-Hill, Inc., New York, pp. 27, 28, and 472, and US patent 3 671 487, 3 723 373, and 3 838 092).
Suitable fluorinated polyolefins E that can be used in pulverulant form are tetrafluoroethylene polymers with median particle diameter of from 100 to 1000 nm and densities of from 2.0 g/cm3 to 2.3 g/cm3. Suitable tetrafluoroethylene polymer powders are commercially available products, and are supplied by way of example by DuPont with trademark Teflon .
Stabilizers used of component E are preferably sterically hindered phenols and phosphites, or a mixture of these, for example Irganox B900 (BASF). It is preferable to use pentaerythritol tetrastearate as mold-release agent.
In another preferred embodiment, additives used are sterically hindered phenols and phosphites, or a mixture of these, other additives used being mold-release agents and pigments, preferably carbon black or titanium dioxide.
Component E also comprises reinforcing and nonreinforcing fillers. Examples of reinforcing fillers are glass beads, mica, silicates, quartz, talc powder, titanium dioxide, wollastonite, and also fumed or precipitated silicas with BET surface areas of at least 50 m2/g (in accordance with DIN 66131/2).
Particular preference is given to talc as filler.
In an alternative embodiment it is possible to use very fine-particle inorganic powders.
It is preferable that the very fine-particle inorganic powders are composed of oxides, phosphates, or hydroxides, preferably of Ti02, Si02, Sn02, ZnO, ZnS, boehmite, Zr02, A1203, aluminum phosphates, iron oxides, or else TiN, WC, A10(OH), Sb203, iron oxides, NaSO4, vanadium oxides, zinc borate, silicates such as Al silicates, Mg silicates, or one-, two-, or three-dimensional silicates.
Mixtures and doped compounds can likewise be used.
These nanoscale particles can moreover have surface-modification by organic molecules in order to achieve better compatibility with the polymers. It is thus possible to produce hydrophobic or hydrophilic surfaces. Particular preference is given to hydrated aluminum oxides, e.g. boehmite, or Ti02.
The median particle diameters of the nanoparticles are smaller than or equal to 200 nm, preferably smaller than or equal to 150 nm, in particular from 1 to 100 nm. The expressions particle size and particle diameter always mean the median particle diameter d50 determined via ultracentrifuge measurements as in W. Scholtan et al., Kolloid-Z. und Z. Polymere 250 (1972), pp. 782-796.
The molding compositions of the invention, comprising components A to D and optionally other known additions E such as stabilizers, dyes, pigments, lubricants and mold-release agents, nucleating agents, and also antistatic agents, are produced by mixing the respective constituents in a known W02013!160371 manner and, at temperatures of from 200 C to 330 C, in conventional assemblies such as internal mixers, extruders, and twin-screw extruders, subjecting them to compounding in the melt or extrusion in the melt.
The present invention therefore also provides a process for the production of thermoplastic molding compositions comprising components A to E which, after mixing, at temperatures of from 200 to 330 C, in commonly used assemblies, are subjected to compounding in the melt or extrusion in the melt.
The mixing of the individual constituents can take place in a known manner either in succession or else simultaneously, and specifically either at about 20 C (room temperature) or else at higher temperature.
The molding compositions of the present invention can be used for the production of moldings of any type. In particular, moldings can be produced via injection molding. Examples of moldings that can be produced are: housing parts of any type, e.g. for household devices, such as TV devices and HiFi devices, coffee machines, mixers, office machines, such as monitors or printers, or protective covering sheets for the construction sector, and parts for the motor vehicle sector.
They are moreover used in the field of electrical engineering, because they have very good electrical properties.
The molding compositions are particularly suitable for the production of thin-walled housing parts in the electrical and electronics sector.
Another type of processing is the production of moldings via blowmolding or via thermoforming from prefabricated sheets or foils.
Production and testing of the molding compositions The starting materials listed in table 1 are compounded and pelletized in a twin-screw extruder (ZSK-25) (Werner and Pfleiderer) at a rotation rate of 225 rpm and a throughput of 20 kg/h, at a melt temperature of 260 C, measured at the die outlet. The finished pellets are processed in an injection molding machine to give the appropriate test samples (unless otherwise noted in tables 1 and 2 the melt temperature was 240 C for flame-retardant compositions and 260 C for non-flame-retardant compositions; mold temperature 80 C, flow front velocity 240 mm/s).
The following methods were used to characterize the properties of the test samples:

BMS 11 1 220 PCT-NAT . - 22 -Melt flowability (MVR) is assessed on the basis of the melt volume flow rate (MVR) measured in accordance with ISO 1133 at a temperature of 240 C (flame-retardant) or 260 C
(non-flame-retardant) and with a ram load of 5 kg.
Fire performance is measured in accordance with UL 94V on specimens measuring 127 x 12.7 x 1.5 mm.
ESC performance was measured in accordance with ISO 4599 (Environmental Stress Cracking (ESC) test) at room temperature (23 C) and at 2.4% outer fiber strain in a hand cream (Sebamed Hand and Nail Balm, based on water, PPG-2, myristyl ether propionate, hydrogenated coconut glycerides, glycerol, glycerol cocoates, hydrogenated coconut oil, sorbitol, panthenol, and Ceteareth-25).
Heat distortion resistance was measured in accordance with DIN ISO 306 (Vicat softening point, method B using 50 N load and a heating rate of 120 K/h) on a single-side-injected test specimen measuring 80 mm x 10 mm x 4 mm.
Yellowness index (YI) is determined on color-sample plaques (CSPs) measuring 60 x 40 x 2 mm in accordance with ASTM standard E313-96 (illuminant: C, observer: 2 , measurement aperture: Large Area Value) in accordance with the equation YI = (128X ¨ 106Z)/Y, where X,Y,Z
= color coordinates in accordance with DIN 5033. The color-sample plaques were injection-molded at 310 C for flame-retardant molding compositions and 320 C for non-flame-retardant molding compositions.
A measure of the processing stability of the resultant compositions is provided by the change (in percent) of the MVR measured in accordance with ISO 1133 at 260 C for non-flame-retardant PC/ABS compositions and at 240 C for flame-retardant PC/ABS compositions using a ram load of 5 kg when the melt is subjected to a temperature of 300 C, with exclusion of air, for a residence time of 15 minutes. The resultant value AMVR(proc.) is calculated via the formula below.
AivivR(proc.)=MVR(after melt aging)¨ MVR(prior to aging) =100%
MVR(prior to aging) The examples below serve for further explanation of the invention.

Examples Component A-1 Linear polycarbonate based on bisphenol A produced by the interfacial process with a weight-average molar mass M of 27 000 g/mol (determined via GPC in dichloromethane with polycarbonate as standard). The BPA content of the polycarbonate A-1 used was 3 ppm. These low BPA contents were obtained by using vacuum to devolatize conventional polycarbonate into an extruder at temperatures above 300 C so that the BPA, which is volatile under these conditions, evaporates. The OH end group content of component A-1 is 150 ppm.
Component A-2 Linear polycarbonate based on bisphenol A produced by the melt process with a weight-average molar mass My, of 27 000 g/mol (determined via GPC in dichloromethane with polycarbonate as standard) (BPA content 32 ppm). The OH end group content of component A-2 is 480 ppm.
Component B-1 ABS graft polymer precipitated under acidic conditions, with core-shell structure, produced by emulsion polymerization of 43% by weight, based on the ABS polymer, of a mixture of 28% by weight of acrylonitrile and 72% by weight of styrene in the presence of 57% by weight, based on the ABS
polymer, of a polybutadiene rubber crosslinked in the form of particles (median particle diameter d50 =
0.35 gm).
Component B-2 ABS graft polymer precipitated under basic conditions, with core-shell structure, produced by emulsion polymerization of 50% by weight, based on the ABS polymer, of a mixture of 23% by weight of acrylonitrile and 77% by weight of styrene in the presence of 50% by weight, based on the ABS
polymer, of a polybutadiene rubber crosslinked in the form of particles (median particle diameter d50 =
0.25 gm).
Component C
Copolymer of 77% by weight of styrene and 23% by weight of acrylonitrile with weight-average molar mass Mw of 130 000 g/mol (determined via GPC), produced by the bulk process.

BMS 11 1 220 PCT--NAT , - 24 -Component D
Bisphenol-A-based oligophosphate 0 Oil 10 = I
= ¨P = ¨

0 -.{¨ CH 3 0 q = 1.1 Component E-1 Coagulated mixture of emulsions of fluorinated polyolefins with emulsions of a copolymer based on styrene-acrylonitrile (Cycolac INP 449 from Sabic).
Component E-2 Pentaerythritol tetrastearate as lubricant/mold-release agent Component E-3 Phosphite stabilizer, Irganox B900 (mixture of 80% Irgafos 168 and 20%
Irganox 1076; BASF
AG; Ludwigshafen / Irgafos 168 (tris(2,4-di-tert-butylphenyl)phosphite) /
Irganox 1076 (2,6-di-tert-buty1-4-(octadecanoxycarbonylethyl)phenol) Component E-4 Pural 200 is used as additional stabilizer (very fine-particle aluminum oxide hydroxide (Condea, Hamburg, Germany), the median particle size of the material being 50 nm).

BMS 11 1 220 PCT-.NAT - 25 -Table 1: Composition and properties of the non-flame-retardant molding compositions Components (pts. by weight) Ex. 1 Ex. 2 Al 70.0 A2 70.0 15.0 15.0 C2 15.0 15.0 E-2 0.5 0.5 E-3 0.1 0.1 Measured BPA content [ppm] 17 76 Properties Vicat B 120 130 129 MVR 260 C/5kg [ccm/10 min] 16.7 26.7 MVR 260 C/5kg after heat-aging 300 C/15 min [ccm/10 mm] 38.7 96.5 delta MVR after heat-aging 300 C/15 min [%] 132 261 ESC test (hand lotion), 2.4%, time to fracture, 260 C [h] 18.0 5.3 Yellowness Index on CSP 320 C 22.3 39.5 From table 1 it can be seen that the composition of the invention as in example 1 exhibits, in comparison with example 2, a smaller rise in the melt flow rate after aging at 300 C, i.e. greater thermal stability of the molecular weight of the polycarbonate. Chemical stability in the hand cream used for testing is also markedly better. At the same time, the Yellowness Index of the low-BPA
content composition at high processing temperatures is smaller. Higher BPA
contents in PC/ABS
compositions therefore lead to impaired technical properties.
The examples in table 1 moreover show that, surprisingly, when graft polymers of component B
precipitated under basic conditions are used in the non-flame-retardant compositions of the invention, using polycarbonate produced by the interfacial process, the rise in the content of free BPA during compounding is markedly smaller (from 2 ppm deriving from the polycarbonate to 17 ppm measured in the compounded composition, i.e. a rise of 15 ppm) than when polycarbonate produced in the melt polymerization process is used (from 22 ppm deriving from the polycarbonate to 76 ppm measured in the compounding composition, i.e. a rise of 54 ppm). For non-flame-retardant compositions using a graft polymer precipitated under basic conditions or comprising basic impurities, it is therefore particularly preferable to use polycarbonate produced by the interfacial process.

Table 2: Composition and properties of the flame-retardant molding compositions .
Components (pts. by weight) Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex.
7 Ex. 8 Ex. 9 Ex. 10 (comp) (comp) (comp) (comp) A-1 77.5 77.5 77.5 77.5 77.5 77.5 77.5 77.5 B-1 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 C 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 D 9.7 9.7 9.7 9.7 9.7 9.7 9.7 9.7 E-1 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 ' E-2 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 E-3 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 =
E-4 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 p Measured BPA content [ppm] 3 22 49 63 96 114 153 207 .32 _.]
Added BPA [ppm] 0 20 40 60 80 ."
r., Properties ,9 Vicat B 120 109 109 109 109 109 UL 94 V at 1.5 mm (7d/70 C) thickness/total after flame time V-0/7s V-0/7s V-0/8s V-0/8s V-0/10s V-0/11s V-0/11s V-0/12s MVR 240 C/5kg [ccm/10 mm] 10.71 10.80 10.97 11.10 11.30 11.40 11.50 11.70 MVR 240 C/5 mm after heat-aging 300 C/15 min [ccm/10 min] _________ 15.90 16.90 17.80 18.30 19.10 19.40 19.90 20.70 delta MVR after heat-aging 300 C/15 mm [%]
48.4 56.4 62.2 64.8 69.0 70.2 73.0 76.9 ESC test (hand cream), 2.4%, time to break, 260 C [h:min:sec] 85:45:00 83:40:00 83:15:00 82:25:00 81:10:00 75:35:00 74:45:00 70:00:00 Yellowness Index on CSP 310 C 29.98 31.16 32.15 33.18 33.22 33.42 33.57 38.05 -Routes by which free, i.e. not chemically bonded, BPA can be entrained into the compositions are by way of example impurity in BPA-based polycarbonate or impurity in BPA-based flame retardants, or else BPA can also arise when the abovementioned components are subjected to thermal stress. In inventive examples 4-6 and also in comparative examples 7-10, defined small proportions of BPA were added to the low-BPA-content polycarbonate A-1 in order to study the effect of BPA. All of the molding compositions were produced under non-aggressive conditions, in order to avoid additional and uncontrolled production of BPA via decomposition of polycarbonate in the molding compositions.
Table 2 collates the properties of flame-retardant PC/ABS compositions with various BPA
contents. Again, in the flame-retardant compositions it is clear that when the compositions of the invention as in examples 3-6 are compared with examples 7-10 they exhibit lower melt viscosities and smaller rises in melt viscosities after aging at 300 C, i.e. markedly higher thermal stability values. Chemical stability in the hand cream used for testing is also markedly better. At the same time, the Yellowness Index of the low-BPA content compositions is smaller.
Higher BPA contents in PC/ABS compositions therefore lead to impaired technical properties, whereas lower BPA
contents smaller than 70 ppm lead, surprisingly, to markedly better properties.

Claims

1. A thermoplastic molding composition comprising A) from 51.0 to 99.5 parts by weight of at least one aromatic polycarbonate, B) from 0.5 to 49.0 parts by weight of at least one graft polymer, C) from 0.0 to 30.0 parts by weight of vinyl (co)polymer and/or polyalkylene terephthalate, D) from 0.0 to 20.0 parts by weight of at least one phosphorus-containing flame retardant, E) from 0.0 to 40.0 parts by weight of other conventional additives, where the sum of the parts by weight of components A) to E) gives a total of 100 parts by weight, and where the content of free bisphenol A in the entire composition is smaller than 70 ppm and greater than 0.5 ppm.

2. The molding composition as claimed in claim 1 comprising A) from 51.0 to 99.5 parts by weight of at least one aromatic polycarbonate, B) from 0.5 to 49.0 parts by weight of at least one graft polymer, C) from 0.0 to 40.0 parts by weight of vinyl (co)polymer and/or polyalkylene terephthalate, E) from 0.0 to 40.0 parts by weight of other conventional additives, where the sum of the parts by weight of components A) to E) gives a total of 100 parts by weight, and where the content of free bisphenol A in the entire composition is smaller than 70 ppm and greater than 0.5 ppm, and where the molding compositions are free from component D.

3. The molding composition as claimed in claim 1 comprising A) from 61.0 to 95.0 parts by weight of at least one aromatic polycarbonate, B) from 0.5 to 20.0 parts by weight of at least one graft polymer, C) from 0.0 to 20.0 parts by weight of vinyl (co)polymer and/or polyalkylene terephthalate, D) from 1.0 to 20.0 parts by weight of at least one phosphorus-containing flame retardant, E) from 0.5 to 20.0 parts by weight of other conventional additives, where the sum of the parts by weight of components A) to E) gives a total of 100 parts by weight, and where the content of free bisphenol A in the entire composition is smaller than 70 ppm and greater than 0.5 ppm.

4. The molding composition as claimed in any of claims 1 to 3, characterized in that the content of free bisphenol A in the entire composition is smaller than 50 ppm and greater than 0.5 ppm.

5. The molding composition as claimed in any of claims 1 to 3, characterized in that the content of free bisphenol A in the entire composition is smaller than 30 ppm and greater than 0.5 ppm.

6. The molding composition as claimed in any of claims 1 to 3, characterized in that the weight-average molar mass Mw of component A is from 26 000 to 32 000 g/mol.

7. The molding composition as claimed in any of claims 1 to 3, characterized in that the OH
end group concentration of component A is smaller than 200 ppm.

8. The molding composition as claimed in claim 7, characterized in that component B) is a graft polymer precipitated under basic conditions or comprising basic impurities, and additionally characterized in that the molding composition comprises no component D.

9. The molding composition as claimed in any of claims 1 to 3, characterized in that component E) present comprises a concentration of from 0.01 to 0.5 parts by weight of at least one stabilizer, alongside optional other additives.

10. The molding composition as claimed in any of claims 1 to 3, characterized in that component E) present comprises a concentration of from 0.05 to 5.0 parts by weight of a fluorinated polyolefin, alongside optional other additives.

11. The molding composition as claimed in any of claims 1 to 3, characterized in that the phosphorus-containing flame retardant (D) is a flame retardant of the general formula (V) in which R1, R2, R3, and R4 are respectively mutually independently optionally halogenated C1 to C8-alkyl, respectively optionally alkyl-substituted, preferably C1to C4-alkyl-substituted, and/or halogen-substituted, preferably chlorine- or bromine-substituted, C5 to C6-cycloalkyl, C6 to C20-aryl, or C7 to C12-aralkyl, n is mutually independently 0 or 1, q is from 0.80 to 5.00, and X is a mono- or polynuclear aromatic moiety having from 6 to 30 C atoms or a linear or branched aliphatic moiety having from 2 to 30 C atoms which can have OH-substitution and can comprise up to 8 ether bonds.

12. The molding composition as claimed in any of claims 1 to 3, in which X
in formula (V) is bisphenol A.

13. The molding composition as claimed in any of claims 1 to 3, comprising graft polymers of B.1) from 5 to 95 parts by weight of a mixture of B.1.1) from 50 to 95 parts by weight of styrene, .alpha.-methylstyrene, methyl-ring-substituted styrene, C1-C8-alkyl methacrylate,C1-C8-alkyl acrylate, or a mixture of these compounds, and B.1.2) from 5 to 50 parts by weight of acrylonitrile, methacrylonitrile, C1-C8-alkyl methacrylates, C1-C8-alkyl acrylate, maleic anhydride, C1-C4-alkyl- or -phenyl-N-substituted maleimides, or a mixture of said compounds, B.2) from 5 to 95 parts by weight of a rubber-containing graft base.

14. The molding composition as claimed in any of claims 1 to 3, comprising, as rubbers of the graft base B.2, diene rubbers, acrylate rubbers, silicone rubbers, silicone-acrylate composite rubbers, or ethylene-propylene-diene rubbers.

15. The composition as claimed in any of claims 1 to 3 comprising, as component E, at least one additive selected from the group consisting of flame retardant synergists, antidripping agents, lubricants and mold-release agents, nucleating agents, stabilizers, antistatic agents, dyes, and pigments.

16. A molding produced from molding compositions as claimed in claim 1.